ScaleIO 2.0.0.3 : Unexpected MDM_DATA_DEGRADED events (rc=BUSY)
Summary: ScaleIO 2.0.0.3 : Unexpected MDM_DATA_DEGRADED events (rc=BUSY)
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Symptoms
Issue Description
Unexpected MDM_DATA_DEGRADED events are logged, without SDS disconnections or other related events.
Note: This KB explains about a specific issue (see Symptoms section). But there can be other causes that lead to the same or similar issues.
Scenario
Possibly under high workload.
Symptoms
MDM_DATA_DEGRADED in MDM's event.
No SDS_DISCONNECTED or SDS_RECONNECTED events.
No related entry in cmatrix log / no SDS found guilty at the same time.
MDM trc shows that the Comb goes degraded, instead of a request from SDS (TGT_ID is the one that moved the state without requesting MDM and getting permission):
05/11 14:01:33.040717 bf4deb8:multiHeadMgr_HandleTgtUpdateCombState:02256: Tgt: #####TGT_ID##### CombId: ##COMBID## raidTgt: #####TGTID###### ProtType: SECONDARY State: 0x10 primaryTgtGenNum: 14 tgtCombCmdGenNum: 3 05/11 14:01:33.040754 bf4deb8:multiHeadRow_MoveState_Inner:02954: [multiHeadRow_InitiateMoveNorm2Degraded:2402]: MultiHead: #MH_ID## Row: 730 NORMAL->DEGRADED (NORM2DEG_SEC_TGT_FAILED)
SDS (TGT_ID) trc shows complains about another SDS (TGTID), on the same comb as above:
05/11 14:01:30.978178 c8ec2eb8:raidComb_WaitForRemoteResponse:05520: (combId=##COMBID##) write to tgtId=#####TGTID###### failed (rc=BUSY) 05/11 14:01:32.040480 c8ec2eb8:raidComb_WaitForRemoteResponse:05520: (combId=##COMBID##) write to tgtId=#####TGTID###### failed (rc=BUSY) 05/11 14:01:33.040399 c8ec2eb8:raidComb_WaitForRemoteResponse:05520: (combId=##COMBID##) write to tgtId=#####TGTID###### failed (rc=BUSY) 05/11 14:01:33.040414 c8ec2eb8:raidComb_ShouldTryAgain:06079: (combId=##COMBID##) allowed attempts or total time exhausted, retry is not allowed. num attempts: 3, total time: 0 millis 05/11 14:01:33.040417 c8ec2eb8:raidComb_UpdateWriteError:01497: Write error comb ##COMBID##, raid state 0x1, local rc SUCCESS, remote rc BUSY 05/11 14:01:33.040420 c8ec2eb8:raidComb_SetCombState:01057: Set comb raid state ##COMBID##, raid state 0x1 => 0x10 (dit) 05/11 14:01:33.874635 c7d52eb8:contCmd_StartMigration:02768: CombId ##COMBID## - Start rc = SUCCESS
Impact
Data degraded but it should recover very soon.
Cause
This is a communication error between two SDS. The "BUSY" return code is returned from network stack but not treated as such. This causes SDS to go degraded without getting permission from MDM.
Resolution
Workaround
N/A. This is usually just temporary network issue.
Impacted versions
2.0.0.3 and below.
Fixed in version
2.0.0.4
2.0.1.0
Article Properties
Article Number: 000052081
Article Type: Solution
Last Modified: 17 Apr 2026
Version: 5
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